Polymer electrolyte membrane and membrane/electrode assembly for polymer electrolyte fuel cell
View Patent ↗A membrane/electrode assembly for a polymer electrolyte fuel cell capable of exhibiting high power generation performance constantly for a long period of time in a high temperature and low humidity environment, and a polymer electrolyte membrane whereby such a membrane/electrode assembly is obtainable. A polymer electrode membrane 15, comprising a proton conductive polymer which has an electrical conductivity of at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and which has a water content of less than 15 mass; and a membrane/electrode assembly 10 comprising an anode 13 and a cathode 14 each having a catalyst layer 11, and a polymer electrolyte membrane 15 disposed between the anode 13 and the cathode 14.
1. A polymer electrolyte membrane, comprising:
a proton conductive fluoropolymer, comprising repeating units having a group of formula (α):
wherein
Q 1 is a perfluoroalkylene group optionally comprising an etheric oxygen atom,
Q 2 is a single bond or a perfluoroalkylene group optionally comprising an etheric oxygen atom,
R fl is a perfluoroalkyl group optionally comprising an etheric oxygen atom,
X is an oxygen atom, a nitrogen atom or a carbon atom,
“a” is 0 when X is an oxygen atom, 1 when X is a nitrogen atom and 2 when X is a carbon atom, and
Y is a fluorine atom or a monovalent perfluoroorganic group wherein
an electrical conductivity of the polymer electrolyte membrane is at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and
a water content of the polymer electrolyte membrane is less than 150 mass %.
2. The polymer electrolyte membrane according to claim 1 , wherein the electrical conductivity is at least 0.08 S/cm at a temperature of 80° C. at a relative humidity of 40%.
3. A membrane/electrode assembly for a polymer electrolyte fuel cell, comprising:
an anode having a catalyst layer;
a cathode having a catalyst layer, and
a polymer electrolyte membrane disposed between the anode and the cathode, wherein
the polymer electrolyte membrane comprises a proton conductive fluoropolymer, comprising repeating units having a group of formula (α):
wherein
Q 1 is a perfluoroalkylene group optionally comprising an etheric oxygen atom,
Q 2 is a single bond or a perfluoroalkylene group optionally comprising an etheric oxygen atom,
R fl is a perfluoroalkyl group optionally comprising an etheric oxygen atom,
X is an oxygen atom, a nitrogen atom or a carbon atom,
“a” is 0 when X is an oxygen atom, 1 when X is a nitrogen atom and 2 when X is a carbon atom, and
Y is a fluorine atom or a monovalent perfluoroorganic group wherein
an electrical conductivity of the polymer electrolyte membrane is at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and
a water content of the polymer electrolyte membrane is less than 150 mass %.
4. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 3 , wherein the electrical conductivity is at least 0.08 S/cm at a temperature of 80° C. at a relative humidity of 40%.
5. A method to generate power, comprising: supplying air of a relative humidity of at most 40% to the cathode of the membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 3 .
6. The method according to claim 5 , further comprising:
maintaining the temperature of the membrane/electrode assembly at 90° C. or higher.
7. A method to generate power, comprising: supplying air of a relative humidity of at most 40% to the cathode of the membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 4 .
8. The method according to claim 7 , further comprising:
maintaining the temperature of the membrane/electrode assembly at 90° C. or higher.
9. A polymer electrolyte fuel cell comprising:
the membrane/electrode assembly according to claim 3 .
10. A polymer electrolyte fuel cell comprising:
the membrane/electrode assembly according to claim 4 .